The present invention relates to an improved vertical belt sanding apparatus adapted for use in forming styrofoam and other expanded synthetic-resinous materials in the manufacture of patterns used in the automobile manufacturing industry. The apparatus is provided with an antifriction bearing at each end of the roller over which the sanding belt operates, to enable the use of sanding belts up to 30 inches (76.2 cm) in width, a vacuum system to prevent belt flutter, and a hinged side gate which is provided with bushing which fit pins affixed to the machine so that the side gate serves as a stiffening member.
Applicant is aware of several previous attempts to improve upon belt sanders. U.S. Pat. No. 2,367,107, issued in 1945 to Emmons, entitled "GRINDING", discloses a vertical belt sander wherein the belt is forced to slidably cling to the surface of the platen by spraying coolant on the belt, forming a film between the belt and platen that holds the belt to the platen by surface tension. U.S. Pat. No. 2,857,717, issued in 1958 to Edgemond, Jr. et al, entitled "BELT SANDER" discloses a belt sander which is convertible for horizontal or vertical use, with a spring-loading system to keep the belt tight as it becomes more flexible with use, a worktable that doubles as a fence, and a grooved platen to induce flexing of the belt. U.S. Pat. No. 3,685,219, issued in 1972 to Palmenberg, entitled "CONTOUR ABRASION MEANS AND METHOD", discloses a belt sander for sanding contoured surfaces, wherein the belt is supported from the platen on a film of pressurized air.
Applicant is also aware of the prior practices in the art of machining Styrofoam and the like in the fabrication of patterns for use in the automotive industry. Disk sanders are used, wherein an abrasive disk is adhesively attached to a rotating disk with a horizontal shaft, and a horizontal worktable pivotable about an axis perpendicular to the axis of the sanding disk. This provides a non-fluttering surface, but has various deficiencies in use. In use, the workpiece to be sanded is placed against the abrasive disk in an area where the disk surface is moving downwardly. Should the workpiece be accidentally moved past the center of the disk to the area where the disk surface is moving upwardly, the abrasive digs into the soft Styrofoam workpiece and the workpiece is often pulled from the operator's hand, ruining the workpiece. The present invention overcomes the above-mentioned deficiencies.